HUNTSVILLE, Ala. -(February 4, 2008) -ADTRAN, Inc. (NASDAQ: ADTN), a leading supplier of next -generation network solutions, has been chronicled in a new best -selling business book, "The Breakthrough Company". The book examines how everyday companies become extraordinary performers. Touted as the most extensive, empirical look at growth companies ever, the book features ADTRAN as one of only nine "breakthrough" companies.

The book, authored by former tech CEO and business school dean, Keith McFarland, reveals the results of more than five years of research where more than 7,000 growth companies seeking to become powerhouses in their industries were studied. McFarland built and analyzed the world's largest growth -company performance database. He interviewed more than 1,500 executives on four continents and conducted intensive 90 -day studies with 52 firms ranging in size from $9 million to $3 billion in annual sales. Eventually, nine breakthrough companies were revealed: ADTRAN, Chico's, Express Personnel, Fastnel, Intuit, Paychex, SAS Institute, and The Staubach Company.

"ADTRAN is a perfect example of how to navigate what we termed as the Business Bermuda Triangle," said McFarland. "ADTRAN has been able to take the core values that helped it gain initial success and has transformed those into sustaining advantages that have helped propel it to nearly one -half billion dollars in annual revenues."

"Many people have asked for ADTRAN's secret to success over the years," said Tom Stanton, CEO of ADTRAN. "Keith's research reinforces what we have said since the beginning - it comes down to who we are and how we do business. We have chosen to follow a different path, truly putting our customer first."

The Wall Street Journal named The Breakthrough Company the #1 National Business Best Seller. The book has also been named a National Best Seller by the New York Times and USA Today. For more information on the book, visit www.breakthroughcompany.com.

About ADTRAN
ADTRAN, Inc. is a leading global provider of networking and communications equipment, with a portfolio of more than 1,600 solutions for use in the last mile of today's telecommunications networks. Widely deployed by carriers and enterprises alike, ADTRAN solutions enable voice, data, video, and Internet communications across copper, fiber, and wireless network infrastructures. ADTRAN solutions are currently in use by every major U.S. service provider and many global ones, as well as by thousands of public, private and governmental organizations worldwide.

For more information, contact the company at 800 9ADTRAN (800 923 -8726) or via email at info@adtran.com. On the Web, visit www.adtran.com.

Featured Product

Sonnen's mission is to provide clean and affordable energy for all. As the first mainstream grid tied residential energy storage company in the world and with 24,000 sonnenBatterie systems installed worldwide, sonnen is a proven global leader in intelligent energy management solutions. The all-in-one sonnenBatterie smart energy storage solution easily integrates with new and existing solar installations to help homes manage their energy throughout the day-saving money, providing backup power, and maximizing the effective use of solar power day and night. Sonnen has won several awards for its energy innovations, including the 2017 Zayed Future Energy Prize, MIT's Technology Review's 50 Smartest Companies in 2016, Global Cleantech 100 for 2015-2017, Greentech Media's 2016 Grid Edge Award for Innovation, and Cleantech's 2015 Company of the Year Award in both Israel and Europe.